330 DERIVATION OF PORCINE INDUCED PLURIPOTENT STEM CELLS FROM FIBROBLASTS OF A TRANSLOCATED AZOOSPERMIC BOAR

Chromosomal rearrangements have a crucial impact on the proper proceedings of meiosis and can lead by several mechanisms to the production of unbalanced gametes or to the complete arrest of gametes production. To assess the impact of these rearrangements in the early development of pig germ cells, we proposed to generate a library of stem cells from infertile boars that are carriers of chromosomal abnormalities as a new tool for the development of an in vitro differentiation system from pluripotent stem cells to germ cells. We report here the reprogramming of fibroblasts from an azoospermic boar carrying a reciprocal translocation t(Y:14) by integrative or nonintegrative viral overexpression of Oct4, Sox2, Klf4, and c-Myc. The iPS cell lines were characterised for pluripotency, cell cycle, and differentiation potential by conventional methods. Genomic stability was analysed by G-banding karyotype, comparative genomic hybridization, and FISH. The porcine iPS-like cell lines harbored characteristics of ground and naïve pluripotency when cultured in specific media. They expressed several pluripotency genes and harbored an ES-like cell cycle. Nevertheless, contrary to mouse and human iPS, they did not silence the integrated exogenes, leading to a poor differentiation potential. Moreover, cytogenetic analysis revealed a high genomic instability upon passaging, which suggests the development of a population with an increased selective advantage. We characterised the selected duplications and compared them to those previously described in other species. In contrast, the nonintegrative reprogrammation system gives us promising results regarding differentiation potential and genomic stability and will bring new insights into the molecular factors controlling and maintaining pluripotency in the pig species.

Bcl2, a transcriptional target of p38alpha, is critical for neuronal commitment of mouse embryonic stem cells

Mouse embryonic stem (ES) cells remain pluripotent in vitro when grown in the presence of leukemia inhibitory factor (LIF) cytokine. LIF starvation leads to cell commitment, and part of the ES-derived differentiated cells die by apoptosis together with caspase3-cleavage and p38alpha activation. Inhibition of p38 activity by chemical compounds (PD169316 and SB203580), along with LIF withdrawal, leads to different outcomes on cell apoptosis, giving the opportunity to study the influence of apoptosis on cell differentiation. By gene profiling studies on ES-derived differentiated cells treated or not with these inhibitors, we have characterized the common and specific set of genes modulated by each inhibitor. We have also identified key genes that might account for their different survival effects. In addition, we have demonstrated that some genes, similarly regulated by both inhibitors (upregulated as Bcl2, Id2, Cd24a or downregulated as Nodal), are bona fide p38alpha targets involved in neurogenesis and found a correlation with their expression profiles and the onset of neuronal differentiation triggered upon retinoic acid treatment. We also showed, in an embryoid body differentiation protocol, that overexpression of EGFP (enhanced green fluorescent protein)-BCL2 fusion protein and repression of p38alpha are essential to increase formation of TUJ1-positive neuronal cell networks along with an increase in Map2-expressing cells.

Uterine compression sutures for postpartum bleeding with uterine atony

OBJECTIVE

To assess the efficacy of a new uterine compression suturing technique in reducing postpartum haemorrhage secondary to severe uterine atony.

DESIGN

Retrospective study.

SETTING

University hospital between December 2000 and March 2006.

POPULATION

Twenty women with uterine atony and postpartum bleeding that did not react to usual medical management.

METHODS

All these women underwent compression suturing of the uterus, in which the anterior and posterior walls of the uterus were attached so as to compress the uterus.

MAIN OUTCOME MEASURES

Arrest of the bleeding, complications and fertility.

RESULTS

Uterine compression suturing was sufficient to stop the bleeding immediately in 95% of the women. None of the women developed complications related to the procedure. All the women recovered normal menstrual cycles. Since uterine compression suturing, eight women have tried to conceive and six (75%) have had a term delivery.

CONCLUSION

Uterine compression suturing is a simple conservative procedure to stop postpartum haemorrhage in the case of failure of the usual management. This surgical technique can be performed quickly and does not seem to decrease fertility.

Murine embryonic stem cell in vitro differentiation: applications to the study of vascular development

The present review summarizes knowledge accumulated during the last decade concerning in vitro endothelial differentiation from embryonic stem (ES) cells. There is now growing evidence that ES cells may provide a powerful model system to determine the cellular and molecular mechanisms of vascular development. ES cells differentiate into the endothelial lineage by successive maturation steps recapitulating in vivo events observed in the embryo. Further maturation of ES-derived embryoid bodies either in three dimensional gels or in confrontation cultures with tumor spheroids can also provide a model of physiological or tumoral angiogenesis. The data obtained from experimental in vitro differentiation of genetically modified mouse ES cells highlight the potential and the complementarity of this model system to in vivo gene knock out studies. We also consider and discuss some of the potential applications of ES cell technology in vascular biology for future directions in basic research and medicine, by manipulation of differentiation and the generation of cell populations for analysis and transplantation for therapeutic use.

Monochorionic monoamnionic twins: vaginal delivery

Monochorionic monoamnionic pregnancies are rare and have a poor obstetric prognosis. A single amniotic sac promotes cord knotting and entanglement with a high risk of fetal anoxia. The response to this risk has been obstetric management consisting of routine cesarean section at 32 weeks of gestation or when pulmonary maturity is attained. This approach is called into question by the series of seven monochorionic monoamnionic pregnancies we present here. Such pregnancies do indeed require increased surveillance to term, but we think it is possible to apply the usual obstetric management of twin pregnancies.

Embryonic stem cell-derived embryoid bodies development in collagen gels recapitulates sprouting angiogenesis

The formation of new blood vessels proceeds by both vasculogenesis and angiogenesis. The development of models, which fully recapitulate spatio-temporal events involved during these processes, are crucial to fully understand their mechanisms of regulation. In vitro differentiation of murine embryonic stem (ES) cells has been shown to be a useful tool to investigate factors and genes potentially involved in vasculogenesis (Hirashima et al, 1999; Risau et al, 1988; Vittet et al, 1996; Wang et al, 1992; Wartenberg et al, 1998). We asked here whether this model system can also recapitulate angiogenesis, which may offer new means to study mechanisms involved in this process. ES-derived embryoid bodies (EBs) obtained after 11 days of differentiation, in which a primitive vascular network had formed, were then subcultured into a type I collagen matrix. In the presence of angiogenic growth factors, EBs rapidly developed branching pseudopods. Whole mount immunostainings with a PECAM antibody revealed that more than 75% EBs displayed, within a few days, a large number of endothelial outgrowths that can give tube-like structures with concomitant differentiation of alpha-smooth muscle actin positive cells, thus evoking sprouting angiogenesis. High expression levels of flk1 (VEGFR2), flt1 (VEGFR1), tie-1, and tie-2 are also found, indicating that budding endothelial cells displayed an angiogenic phenotype. The endothelial sprouting response was specifically induced by angiogenic factors with a major contribution of vascular endothelial growth factor (VEGF). Known angiostatic agents, such as platelet factor 4 (PF4), angiostatin, and endostatin inhibited the formation of endothelial sprouts induced by angiogenic factors. Moreover, consistent with the in vivo phenotype, VE-cadherin deficient EBs failed to develop angiogenesis in this model. ES cell differentiation can then recapitulate, in addition to vasculogenesis, the early stages of sprouting angiogenesis. This model system, in which genetic modifications can be easily introduced, may be of particular interest to investigate unsolved questions and molecular mechanisms involved in blood vessel formation.

Antenatal diagnosis of Bart's hydrops fetalis [correction of homozygous alpha thalassemia]. A case report

OBJECTIVE

Diagnosis of the Bart's hydrops fetalis [corrected].

METHOD

Bart's hydrops fetalis [corrected] was discovered by chance in the fetus of a female Chinese patient. Major intrauterine growth retardation, oligohydramnios, an immobile fetus, and cardiomegaly were the principal echographic signs. Cordocentesis showed fetal anemia, and electrophoresis of fetal hemoglobin revealed the presence of Bart's hemoglobin.

RESULT

As there is no known effective treatment, termination of pregnancy was proposed to the patient.

CONCLUSIONS

Bart's hydrops fetallis [corrected] is a lethal condition. Early echographic signs (cardiothoracic index >0.50, placental thickening) can be screened during weeks 17-18 or even during weeks 13-14 of gestation. These signs would permit a reduction of invasive examinations in couples at risk.